This isn’t that huge of a revelation. Bishop Fellay said almost exactly that 10 years ago in a newsletter and was later accused of being a sedevacantist by Fr. Pfeiffer. Bishop Fellay was even a bit more precise. But recalling from memory he said one day it may be determined that Francis never was pope at all. And several more things.
Remember that when Bishop Williamson met with Fr. Gruner in Canada seven years ago or so, he also gave credence to the “Benedict is the true pope” group. There are other videos as well where Bishop Williamson casts doubts on the papacy of Francis long ago. I compiled one somewhere on one of my accounts for youtube years ago. Bishop Williamson has also publicly revealed that he regards the Thuc consecrations as valid.
All these facts slam in the face of the resistance folks who like to promote a position that you are not even allowed to think in your mind privately any doubt regarding the papacy of Francis. I believe Sean Johnson was one of those crowd who used the universal acceptance argument and held it to be objectively sinful to doubt the papacy of Francis (or schismatic). And there are plenty more layfolks in R and R camps who hold wild ideas about the papacy. Brazilian resistance laity have asserted with me that if the Dalai Lama were to be elected from a conclave, I would have to accept him as my pope (something I find which favors the religious indifferentism of masonry).
So no I do not see this as a Christmas miracle. Bishop Williamson has held this view publicly for nearly a decade and is a lot softer on sedevacantists than the laity who claim to follow him.